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Recognizing mourning flies

Fungus gnats or fungus flies are black in color, 1-3 mm in size and fly quite slowly. Many people think they resemble small black flies or fruit flies.

Verschil fruitvliegje en rouwvliegje

Fungus gnats vs fruit flies

How do I tell the difference between mourning flies and fruit flies? Fruit flies are shorter and broader built with red eyes and short antennae. Mourning flies are slender, have long legs and antennae, and are black in color. You often see fruit flies around the fruit basket or organic waste bin, while mourning flies prefer to sit near the plants.

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Mourning flies vs sewer flies

Sewer flies, latrine flies or moth mosquitoes, just like mourning flies, are attracted to damp places. However, in appearance they look very different from the mourning flies. The wings of sewer flies are much larger and rounder in shape. The sewer flies are also lighter in color and hairier than the mourning flies.

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Fungnus gnat size

Mourning flies are very small, only a few millimeters in size.

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Gnat or fly

Mourning flies are not actually flies, but gnats. They belong to the family of sciarid flies (Sciaridae) and are therefore also called sciarid flies. This family contains more than 2,000 species, mostly found in tropical areas. Don't worry: unlike some gnats, mourning flies will not sting.

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Mourning fly larva

To see the larva of the fungus fly, you have to dig around in the soil of the plant. The larvae are transparent in color, with a black head.

Mourning flies development

Mourning flies develop relatively quickly. An adult mourning fly only lives for 1 week and can lay up to 300 new eggs during this week. A larva hatches from the egg after 2 days. The larva lives underground and eats organic material. When the larvae have eaten enough, the larvae pupate into adult mourning flies. The pupal stage lasts a few days. In total, the development from egg to adult fungus fly takes about 25 days at room temperature.

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Mourning flies damage


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Combating fungus flies

Mourning flies can be controlled easily and effectively with two different products: Felti nematodes and Sticky Leaf sticky traps. This way you tackle all life stages of the mourning fly.

Controlling the larvae of mourning flies
The larvae of mourning flies can be easily controlled with Felti nematodes. Nematodes are microscopic worms that parasitize the larvae of mourning flies, causing them to die. The Felti product comes in a clay-like substance that you can dissolve in water. Pour the solution of nematodes and water over the potting soil and the nematodes do all the work.

Controlling adult mourning flies
Adult mourning flies can be controlled by catching them with large or small sticky traps. The attractive color attracts the mourning flies and the strong glue prevents them from escaping. Traps are odorless and contain no toxins. Traps are ideal for good pest monitoring. You can quickly see if you are dealing with an infestation and can therefore take timely action by releasing Felti nematodes.

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Fungus gnat control with nematodes

The Felti nematodes are small but very effective in controlling fungus fly larvae in the soil.

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Catch adult fungus gnats

Effectively catch mourning flies with the Sticky Leaf Green Mini trapping cards. The green leaves look beautiful and inconspicuous in the houseplants.

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Preventing fungus flies

You can prevent mourning flies by making the environment less favorable for mourning fly larvae and by using natural enemies preventively.

Mourning flies can get into your plants in several ways. Often newly purchased plants are infested with eggs or larvae of mourning flies. Therefore, it is advisable to set the new plants apart in a room or outside for a few days.

Improve plant drainage
Pay close attention to the drainage of your (indoor) plants. With many plants, if the roots are in water for too long, they will turn brown and rot. This is called root rot. The larvae of mourning flies really like mold and a wet environment. Lift the plant's inner pot occasionally. This way you can inspect whether the roots are nice and white in color and look healthy. In the case of pots in the garden or on the balcony, make sure there are holes in the bottom of the pot so that the water does not remain in the pot.

Use nematodes preventively
An effective way to prevent mourning flies is to preventively add Felti nematodes to plants. Add the nematodes to the amount of water you normally give to the plant.

Other ways to control fungus gnats

Control mourning flies with ant powder or other chemicals
There are many different anti-insect agents on the market that claim to be 100% natural, ecological or organic. Unfortunately, these remedies may still contain toxic substances that are originally natural. The problem with these products is that they very commonly and effectively kill insects that come in contact with them.

If used outdoors, for example, it can wash off the leaves and end up in water. The toxins can be harmful to critters that live in the water. They are also not nice for pets, children or your own health. Always look for the composition on the packaging. Look for toxins such as pyrethrins, deltamethrin or acetamiprid and rather avoid them.

Control mourning flies with cinnamon
Some people control mourning flies by mixing cinnamon with boiling water. This mixture is poured at the plants after it has cooled. This technique is also used with thyme. The herbs are then said to have a repellent effect.

Controlling mourning flies with coffee
By spreading coffee grounds over the potting soil, you chase away the adult mourning flies. Because of the strong smell, they prefer not to lay eggs in the potting soil. With this technique, you do not control the larvae of mourning flies in the potting soil.

Controlling mourning flies with garlic
By putting garlic cloves in the plant you ensure that mourning flies are less eager to lay eggs in the potting soil. Unfortunately for yourself, this is not a nice smell either! The garlic does not control or eliminate the larvae of the mourning flies.